1. Field of the Invention
The present invention is directed to computer systems. More particularly, it is directed to graphical image processing including the generation of shadows with penumbra.
2. Description of the Related Art
Light emanating from a point will not have a penumbra as the shadow acceptor will either receive no light or full light. Penumbrae from area light sources are done on the CPU by either stochastic ray casting or by other generally execution-expensive geometrical projections. Shadows from such point light sources have been calculated on the GPU from some time using various types of shadow maps that generally include only depth information, such as indicating a distance between a light source and a shadow caster. Such techniques may not well-suited for calculating light from area light sources.